Hello,
we have linksys SPA 9000
Software Version: 6.1.5 Hardware Version: 1.2.5(a)
some times ago we found that linksys stoped to save the configuration and reboot after clicking on "submit all changes".
Example:
we change host name from "n27-voip-01" to "n27-voip-02" and click submit all changes, right after that with no timeout we can log on the spa and there is no changes in hostname.